The oncogenic receptor tyrosine kinase (RTK) ERBB2 is known to dimerize with other EGFR family members, particularly ERBB3, through which it potently activates PI3K signalling. Antibody-mediated ...inhibition of this ERBB2/ERBB3/PI3K axis has been a cornerstone of treatment for ERBB2-amplified breast cancer patients for two decades. However, the lack of response and the rapid onset of relapse in many patients now question the assumption that the ERBB2/ERBB3 heterodimer is the sole relevant effector target of these therapies.
Through a systematic protein-protein interaction screen, we have identified and validated alternative RTKs that interact with ERBB2. Using quantitative readouts of signalling pathway activation and cell proliferation, we have examined their influence upon the mechanism of trastuzumab- and pertuzumab-mediated inhibition of cell growth in ERBB2-amplified breast cancer cell lines and a patient-derived xenograft model.
We now demonstrate that inactivation of ERBB3/PI3K by these therapeutic antibodies is insufficient to inhibit the growth of ERBB2-amplified breast cancer cells. Instead, we show extensive promiscuity between ERBB2 and an array of RTKs from outside of the EGFR family. Paradoxically, pertuzumab also acts as an artificial ligand to promote ERBB2 activation and ERK signalling, through allosteric activation by a subset of these non-canonical RTKs. However, this unexpected activation mechanism also increases the sensitivity of the receptor network to the ERBB2 kinase inhibitor lapatinib, which in combination with pertuzumab, displays a synergistic effect in single-agent resistant cell lines and PDX models.
The interaction of ERBB2 with a number of non-canonical RTKs activates a compensatory signalling response following treatment with pertuzumab, although a counter-intuitive combination of ERBB2 antibody therapy and a kinase inhibitor can overcome this innate therapeutic resistance.
Considerable amount of experimental work has been performed to elucidate the behavior of granular flow inside a rotating drum but yet it is not completely understood. Furthermore, most of these ...investigations have involved spherical or nearly spherical particles. The extent of the experiments involving non-spherical particles previously carried out was limited by the experimental techniques available for the studies. In this work, a simple imaging method and a speckle visibility spectroscopy (SVS) technique were used to measure the volume fraction and granular temperature of irregular glass sand particles under the slumping regime within a rotating drum. By comparing the temporal variation of the volume fraction of the granular bed with SVS measurement, we found the compaction and dilatancy of the granular flow during a slumping cycle can be easily characterized by granular temperature temporal curves. At different rotating speeds, we found the lower repose angle increases linearly with the rotational speed and the compaction duration is inversely proportional to the critical angle of compaction. We find, in addition, the compaction induced relative motion of particles decreases with the increase of rotational speed, while the avalanche induced motion of particles is independent of rotational speed. Finally, using the mathematical model of avalanche duration and angle of repose proposed by Mellmann to calculate the particle avalanche duration, we found that the compaction of the particle system shortens the avalanche duration.
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•The compaction is observed before while dilatancy occurs during avalanches.•The compaction due to irregular particle shape shortens duration of avalanche.•Duration of compaction is inversely proportional to the critical angle of compaction.•Compaction induced granular temperature increase with rotational speed.•Avalanche induced granular temperature independent of rotational speed.
Combinations of entomopathogenic nematodes Steinernema longicaudum X-7 and Heterorhabditis bacteriophora H06 with chlorantraniliprole, diflubenzuron, and imidacloprid insecticides at different rates ...for the control of the white grub, Holotrichia oblita Faldermann (Coleoptera: Scarabaeidae), were evaluated both in the laboratory and in peanut fields. In the laboratory, the combinations had a synergistic or additive effect on the second-instar larvae of H. oblita and caused faster mortality than one nematode species or insecticide alone. Heterorhabditis bacteriophora–chlorantraniliprole and H. bacteriophora–imidacloprid showed synergistic effects on the larvae. When higher concentrations of the insecticides were combined with nematodes, the stronger synergistic effects were found. In peanut fields, S. longicaudum–imidacloprid, H. bacteriophora–imidacloprid, or H. bacteriophora–chlorantraniliprole also showed synergistic effects against the larvae. The three nematode–insecticide combinations produced similar percentage reductions of the grub larvae and less percentages of injured legumes, compared with the chlorpyrifos treatment. Cost–benefit analysis showed that H. bacteriophora 5.0 × 103 infective juveniles (IJs) per plant (equal to 7.5 × 108 IJ ha–1) combined with imidacloprid at the recommended concentration is a practical strategy for the practitioner to manage the white grubs in the peanut production.
•Unsupervised MR-CT deformable registration network using image synthesis and dual-channel registration.•Image synthesis using probabilistic CycleGAN converts multi-modality registration into ...mono-modality registration in both MR and CT channel.•Dual-channel registration estimates stationary velocity field in MR and CT channel and fuses the two into a single diffeomorphic deformation field.•End-to-end training strategy jointly optimizes image synthesis and registration subnetworks.
The accuracy of minimally invasive, intracranial neurosurgery can be challenged by deformation of brain tissue – e.g., up to 10 mm due to egress of cerebrospinal fluid during neuroendoscopic approach. We report an unsupervised, deep learning-based registration framework to resolve such deformations between preoperative MR and intraoperative CT with fast runtime for neurosurgical guidance.
The framework incorporates subnetworks for MR and CT image synthesis with a dual-channel registration subnetwork (with synthesis uncertainty providing spatially varying weights on the dual-channel loss) to estimate a diffeomorphic deformation field from both the MR and CT channels. An end-to-end training is proposed that jointly optimizes both the synthesis and registration subnetworks. The proposed framework was investigated using three datasets: (1) paired MR/CT with simulated deformations; (2) paired MR/CT with real deformations; and (3) a neurosurgery dataset with real deformation. Two state-of-the-art methods (Symmetric Normalization and VoxelMorph) were implemented as a basis of comparison, and variations in the proposed dual-channel network were investigated, including single-channel registration, fusion without uncertainty weighting, and conventional sequential training of the synthesis and registration subnetworks.
The proposed method achieved: (1) Dice coefficient = 0.82±0.07 and TRE = 1.2 ± 0.6 mm on paired MR/CT with simulated deformations; (2) Dice coefficient = 0.83 ± 0.07 and TRE = 1.4 ± 0.7 mm on paired MR/CT with real deformations; and (3) Dice = 0.79 ± 0.13 and TRE = 1.6 ± 1.0 mm on the neurosurgery dataset with real deformations. The dual-channel registration with uncertainty weighting demonstrated superior performance (e.g., TRE = 1.2 ± 0.6 mm) compared to single-channel registration (TRE = 1.6 ± 1.0 mm, p < 0.05 for CT channel and TRE = 1.3 ± 0.7 mm for MR channel) and dual-channel registration without uncertainty weighting (TRE = 1.4 ± 0.8 mm, p < 0.05). End-to-end training of the synthesis and registration subnetworks also improved performance compared to the conventional sequential training strategy (TRE = 1.3 ± 0.6 mm). Registration runtime with the proposed network was ∼3 s.
The deformable registration framework based on dual-channel MR/CT registration with spatially varying weights and end-to-end training achieved geometric accuracy and runtime that was superior to state-of-the-art baseline methods and various ablations of the proposed network. The accuracy and runtime of the method may be compatible with the requirements of high-precision neurosurgery.
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Germline loss-of-function variation in TNFAIP3, encoding A20, has been implicated in a wide variety of autoinflammatory and autoimmune conditions, with acquired somatic missense mutations linked to ...cancer progression. Furthermore, human sequence data reveals that the A20 locus contains ~ 400 non-synonymous coding variants, which are largely uncharacterised. The growing number of A20 coding variants with unknown function, but potential clinical impact, poses a challenge to traditional mouse-based approaches. Here we report the development of a novel functional genomics approach that utilizes a new A20-deficient zebrafish (Danio rerio) model to investigate the impact of TNFAIP3 genetic variants in vivo. A20-deficient zebrafish are hyper-responsive to microbial immune activation and exhibit spontaneous early lethality. Ectopic addition of human A20 rescued A20-null zebrafish from lethality, while missense mutations at two conserved A20 residues, S381A and C243Y, reversed this protective effect. Ser381 represents a phosphorylation site important for enhancing A20 activity that is abrogated by its mutation to alanine, or by a causal C243Y mutation that triggers human autoimmune disease. These data reveal an evolutionarily conserved role for TNFAIP3 in limiting inflammation in the vertebrate linage and show how this function is controlled by phosphorylation. They also demonstrate how a zebrafish functional genomics pipeline can be utilized to investigate the in vivo significance of medically relevant human TNFAIP3 gene variants.
Carbon nanotube field‐effect transistors (NTFETs) coated with poly(ethyleneimine) (PEI) and starch polymers exhibit electrical conductance changes upon exposure to CO2 gas in air at ambient ...temperature (see Figure). This observation has furnished nanoelectronic CO2 sensors. Their small size and low power consumption has enormous potential in wireless sensing for industrial and medical CO2 sensor units.
The dynamic assembly of multiprotein complexes is a central mechanism of many cell signaling pathways. This process is key to maintaining the spatiotemporal specificity required for an accurate, yet ...adaptive, response to rapidly changing cellular conditions. We describe a technique for the specific isolation and downstream proteomic characterization of any two interacting proteins, to the exclusion of their individual moieties and competing binding partners. We termed the approach bimolecular complementation affinity purification (BiCAP) because it combines the use of conformation-specific nanobodies with a protein-fragment complementation assay with affinity purification. Using BiCAP, we characterized the specific interactome of the epidermal growth factor receptor (EGFR) family member ERBB2 when in the form of a homodimer or when in the form of a heterodimer with either EGFR or ERBB3. We identified dimer-specific interaction patterns for key adaptor proteins and identified a number of previously unknown interacting partners. Functional analysis for one of these newly identified partners revealed a noncanonical mechanism of extracellular signal-regulated kinase (ERK) activation that is specific to the ERBB2:ERBB3 heterodimer and acts through the adaptor protein FAM59A in breast cancer cells.
Microtubules (MT) are critical cytoskeletal filaments that have several functions in cell morphogenesis, cell division, vesicle transport and cytoplasmic separation in the spatiotemporal regulation ...of eukaryotic cells. Formation of MT requires the co‐interaction of MT nucleation and α–β‐tubulins, as well as MT‐associated proteins (MAP). Many key MAP contributing to MT nucleation and elongation are essential for MT nucleation and regulation of MT dynamics, and are conserved in the plant kingdom. Therefore, the deletion or decrease of γ‐tubulin ring complex (γTuRC) components and related MAP, such as the augmin complex, NEDD1, MZT1, EB1, MAP65, etc., in Arabidopsis thaliana results in MT organizational defects in the spindle and phragmoplast MT, as well as in chromosome defects. In addition, similar defects in MT organization and chromosome structure have been observed in plants under abiotic stress conditions, such as under high UV‐B radiation. The MT can sense the signal from UV‐B radiation, resulting in abnormal MT arrangement. Further studies are required to determine whether the abnormal chromosomes induced by UV‐B radiation can be attributed to the involvement of abnormal MT arrays in chromosome migration after DNA damage.
Microtubule organization plays a role in response to abiotic stressors through unstable microtubule dynamics.
Summary
Acute ischaemic stroke can induce secondary brain injury by activating an inflammatory response that contributes to clinical impairment. As a specific inhibitor of the immunoproteasome ...subunit low molecular weight polypeptide 7 (LMP7), PR‐957 may participate in regulating pathophysiological and inflammatory responses in multiple diseases of the central nervous system (CNS). We investigated the neuroprotective properties of PR‐957 in a mouse model of stroke, induced by middle cerebral artery occlusion (MCAO). After MCAO and injections of PR‐957 or vehicle, we evaluated mice behaviourally using modified Neurological Severity Scores (mNSS) and sensorimotor tests, including the adhesive‐removal test, a foot‐fault test and an inclined plane test. Infarct volume was measured 24 and 72 h after MCAO. Infiltration by different lymphocyte subpopulations was evaluated by flow cytometry and immunofluorescent staining of brain tissue from the penumbral area. Quantitative real‐time polymerase chain reaction analysis and enzyme‐linked immunosorbent assay were used to measure the expression of proinflammatory cytokines: interkeukin (IL)‐1α, IL‐1β, IL‐2, IL‐4, IL‐6, IL‐10, IL‐12, IL‐17A, interferon (IFN)‐γ, tumour necrosis factor (TNF)‐α, granulocyte colony‐stimulating factor (GCSF) and granulocyte–macrophage colony‐stimulating factor (GM‐CSF). Expression of phosphorylated signal transducer and activator of transcription 3 (pSTAT‐3) protein levels in brain was measured by immunoblot. MCAO mice treated with PR‐957 showed a significant decrease in infarct volume and had mild neurological deficits compared to vehicle‐treated mice. PR‐957 administration also significantly decreased IL‐1β, IL‐6, IL‐12, IL‐17A and TNF‐α. PR‐957 provides neuroprotection via inhibiting T lymphocyte infiltration and decreasing T helper type 17 (Th17) cell differentiation in MCAO mice, which may result from the reduced expression of pSTAT‐3. The neuroprotective effect of PR‐957 indicates its potential utility as anti‐inflammatory therapy for ischaemic stroke.
In this study,we investigated the neuroprotective properties of PR‐957 in a mouse model of stroke, induced by middle cerebral artery occlusion (MCAO). PR‐957 provides neuroprotection via inhibiting T lymphocyte infiltration and decreasing Th17 cell differentiation in MCAO mice, which may result from suppression of the STAT3/RORγt pathway.
Study on transcriptome, the entire pool of transcripts in an organism or single cells at certain physiological or pathological stage, is indispensable in unraveling the connection and regulation ...between DNA and protein. Before the advent of deep sequencing, microarray was the main approach to handle transcripts. Despite obvious shortcomings, including limited dynamic range and difficulties to compare the results from distinct experiments, microarray was widely applied. During the past decade, next-generation sequencing (NGS) has revolutionized our understanding of genomics in a fast, high-throughput, cost-effective, and tractable manner. By adopting NGS, efficiency and fruitful outcomes concerning the efforts to elucidate genes responsible for producing active compounds in medicinal plants were profoundly enhanced. The whole process involves steps, from the plant material sampling, to cDNA library preparation, to deep sequencing, and then bioinformatics takes over to assemble enormous-yet fragmentary-data from which to comb and extract information. The unprecedentedly rapid development of such technologies provides so many choices to facilitate the task, which can cause confusion when choosing the suitable methodology for specific purposes. Here, we review the general approaches for deep transcriptome analysis and then focus on their application in discovering biosynthetic pathways of medicinal plants that produce important secondary metabolites.
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